#include "Date.h"

Date::Date(int year, int month, int day)
{
	_year = year;
	_month = month;
	_day = day;
}

//修饰的是 Date* this
void Date::Print() const
{
	cout << _year << "-" << _month << "-" << _day << endl;
}

bool Date::operator<(const Date& d) const
{
	if (_year < d._year)
	{
		return true;
	}
	else if (_year == d._year)
	{
		if (_month < d._month)
		{
			return true;
		}
		else if (_month == d._month)
		{
			return _day < d._day;
		}
	}
	return false;
}

bool Date::operator<=(const Date& d) const 
{
	return *this < d || *this == d;
}

bool Date::operator>(const Date& d) const
{
	return !(*this <= d);
}

bool Date::operator>=(const Date& d) const
{
	return !(*this < d);
}

bool Date::operator==(const Date& d) const
{
	return _year == d._year
		&& _month == d._month
		&& _day == d._day;
}

bool Date::operator!=(const Date& d) const
{
	return !(*this == d);
}

Date& Date::operator+=(const int day)
{
	if (day < 0)
	{
		return *this -= -day;
	}

	_day += day;
	while (_day > getmonthday(_year, _month))
	{
		_day -= getmonthday(_year, _month);
		_month++;
		if (_month == 13)
		{
			_year++;
			_month = 1;
		}
	}
	return *this;
}

//不能传引用 因为tmp销毁了
Date Date::operator+(const int day) const
{
	Date tmp = *this;
	tmp += day;
	return tmp;
}

Date& Date::operator-=(const int day) 
{
	if (day < 0)
	{
		return *this += -day;
	}

	_day -= day;
	while (_day <= 0)
	{
		--_month;
		if (_month == 0)
		{
			_year--;
			_month = 12;
		}
		_day += getmonthday(_year, _month);
	}
	return *this;
}

Date Date::operator-(const int day) const
{
	Date tmp = *this;
	tmp -= day;
	return *this;
}

//默认为前置++
Date& Date::operator++()
{
	 return *this += 1;
}

//后置++
Date Date::operator++(int)
{
	Date tmp = (*this);
	*this += 1;
	return tmp;
}

Date& Date::operator--()
{
	return *this -= 1;
}

Date Date::operator--(int)
{
	Date tmp = (*this);
	*this -= 1;
	return tmp;
}

int Date::operator-(const Date& d) const
{
	Date max_d = *this;
	Date min_d = d;
	int flag = 1;
	if (max_d < min_d)
	{
		max_d = d;
		min_d = *this;
		flag = -1;
	}
	int n = 0;
	while (min_d != max_d)
	{
		++n;
		++min_d;
	}
	return n * flag;
}


ostream& operator<<(ostream& out, const Date& d)
{
	out << d._year << "年" << d._month << "月" << d._day << "日" << endl;
	return out;
}

istream& operator>>(istream& in, Date& d)
{
	in >> d._year >> d._month >> d._day;
	return in;
}